Dry method of preparing lead compounds.



PATENTED FEB. 13, 1906 v J. P. NEVILLE.

DRY METHOD 0Fv PREPARING LEAD COMPOUNDS.

APPLIOATION FILED AUG. 29, 1905.

UNLiTED STATES FFIGE.

JOHN P. NEVILLE, OF OAKLAND, CALIFORNIA.

DRY M ETHGD OF PREPARING LEAD COMPOUNDS.

Specification of Letters E'atent.

Application filed Augnstfig, 1906. Serial No. 276.246.

Patented Feb. 13, 1906'.

To (ZZZ whom itmay concern: Be it known that 1, JOHN P. NEVIL E, a citizen of the United States, residing in the city of Oakland, county of Alameda, State of California, have invented certain new and useful improvements inDry Methods of Preparing Lead Compounds; and I hereby declarethe followin to be a full, clear, and exact description of t e same.

The resent invention relates to the treatment or lead compounds as received from the corroding pans and furnaces, the objectbeing to reduce the lead carbonates and oxicls so received in a dry condition instead of using moisture for the purpose of reducin the material received from the said corroding pans and furnaces.

The method at present most generally resorted to in the treatment of lead carbonate and oxide for commercial pu oses is to separate the metallic lead from the carbonate of lead and then to mix the carbonate of lead with water to form a ulp, which is ground by running the mass t irough suitable burstones, thence adding additional Water, and stirring until the ground material is of the consistency of milk, which is then passed throu h a series of settling-tubs. In the first of t ese tube the coarse carbonate of lead settles and is collected for regrinding, the fine particles float over into the successive tubs and finally settle into the consistency of thick cream. This thick heavy mixture of carbonate of lead is then placed on large copper pans, which are heated until the water is evaporated. Such method requires from one week to ten days in which to successfully treat the cmaterial and place the same in condition for commercial pur oses.

The improve method consists in subjecting the carbonate of lead to the action of a high-speed pulverizer, so as to reduce the same to a fine impalpable powder, the owder so produced being through the me ium of an air-suction drawn from within the pulverizer and caused to spread in a thin layer during its course of upward travel to an ar rester, into which the powder-laden air is discharged. The heavier particles of the pulverized lead carbonate settle within the arrester by gravity and fall into a settling or storage bin located thereunder to receive such particles, while the lighter particles of the powdered lead carbonate are carried from the arrester by the outward current of air and deposited within a suitable collector,into

which the particles of lead carbonate are separated from the body of air escaping therefrom. To facilitate the separation of the lead particles within the arrester, the dustladen air entering therein is 'iven a whirling action which confines the body of air therein for a longer period of time and ermits of a the mixing. of the carbonate of lead with water and the grinding of the lead-pulp thus formed being dispensed with, likewise the time consumed in decanting the ground and rewatered material and in drying out the collected material being saved. The result is the treatment of a larger quantity of material er day, a lessening of the time required to ace the carbonate of lead in a commercia condition, andthe treating of the material at a considerably-lessened expense.

In order to destroy any particle of tanbark or other organic matter, also any acetate of lead which may be contained in the lead'carbonate, so as to im rove the product and produce a finer and w iter quality of white lead, the current of lead-laden air is caused to pass tb ough an atmosphere of gas, such as ozone, which oxidizes and eliminates the foreign substances, thereby freeing the pulverized particles of lead carbonate of its impurities.

It will be understood that the foregoing method ap lies equally as well in the treatmentof re lead and lithargeand pigment.

In the drawing accompanying the present application an apparatus foi successfully carrying out the described method is illustrated, the drawing disclosing a longitudinal vertical sectional View of the apparatus.

Inbrief, the a paratus comprises a pulver- I izer 1, into whic the material to be treated is delivered by the feed 2. Above the pulverizer is arranged a funnel 3, which is suralso an open one, and it communicates with The inner funnel has an open bottom 5,

IIO.

eeives the pulverized material.

the said funnel is formed with a closed top the chamber 6 of the pulverizer, which re- However,

wall 7, through which wall extends a suctionpipe 7. The said suction-pipe communicates with the exhauster 8, within which works a suction-fan i". From the exhauster leads an outlet-pipe 9, which enters an inverted-cone-shaped arrester 9. This arrester is mounted above the settling chamber or bin 10, the bottom thereof being opened so as to establish a. direct communication between the interior of the arrester and the settling chamber or bin 10.

The arrester is provided with a closed top 11, through which extends an outlet-pi e 12.. -'lhe lower end of this pipe enters a col ector 12, within which a series of plates 13 is secured. The outlets 13 of the collector are covered with any suitable fine-mesh coverin 14, which acts to strain the escapin air 0 any particles of line lead carried there y.

Intermediate the exhauster 8 and the arrester 9 there is introduced an electrical generator 14 for the creating of ozone, which gas is discharged into the connecting or outlet pipe 9, so as to impregnate the dust-laden air passing therethrough with the said gas, in order to oxidize and eliminate any foreign substance and oxidize any acetate of lead which may be contained in the particles of lead carbonates.

rectly into the pulverizer, where it is ground into a line powder. At the same time the exhaust-fan is put into operation, so as to create sull'icient suction to raise the pulverized material within the annular passageway 5, liftim-"the same over the upper e of the funnel 3 and drawing the same as a thin film in a horizontal direction toward the suction-pipe 7, into which it enters and is delivered by the outlet pipe 9 into the arrester 9. Such of the raised particles as are too heavy to float as conveyed toward the suction-pipe 7 fall by gravity into the open funnel 3 and are redelivered to-the pulverizer 1 for recrushing. The dust-laden air as conveyed from the exhauster to the arrester is impre nated with ozone, which gas oxidizes and eliminates such foreign substances and oxidizes, such acetate of lead as may be contained therein. As the dustladen air enters the arrester the heavier particles contained therein fall by' gravity and enter the settling chamber or bin 10', while the lighter particles are carried off through the pipe 12 Y and are delivered with the air into the collector 12. The flow of air is arrested Within the collector 12 by the baffle-plates 13 and the particles of lead carbonate contained within the air permitted to settle in the collector. Such of the material as fails to settle owing to its extreme lightness will be strained from the air and recovered as the air escapes through the mesh-covered outlets 13.

Havin thus described the invention, what is claimed as new, and desired to be protected by Letters Patent, is

1. The dry method of preparing white lead,

red lead and litharge for commercial use.

which consists in subjecting the material to be treated to the action of a pulverizer to reduce it into apowder, withdrawing by air-suction the powder from within the pulverizer, and discharging the dust-laden air into an arrester wherein the h'avier particles of carbonate of lead separate by gravity from the laden air.

2. The dry method of reparing white lead, red lead and litharge? which consists in. converting the material to be treated into a powder, withdrawin the powdered material by air-suction, disc arging the dust-laden air into-an arrester wherein the heavier particles of lead separate by gravity from the laden air, and finally discharging the air from the arrester into a collector to free the air of any particles of carbonate of lead carried thereby.

3. The dry method of preparing carbonate of lead for commercial use, the same consisting in reducing the material to be treated into a powder, withdrawing by air-suction or commercial use,

of lead for commercial use, which consists in reducin the material to be treated to a powder, wit drawing the powder thus formed by a fiowin body of air, and impregnating the flowing ody of dust-laden air with a gas such as ozoneto oxidize and eliminate all foreign substance and oxidize such acetate of lead as may be contained in the owdered carbonate carried by the bod 0 air, and

finally separating the dust la en air of the particles of lead carbonate held therein.

In testimony whereof I have hereunto set my hand. 1

JOHN P. NEVILLE. Witnesses:

J. COMPTON, D..P RICHARDS. 

